1. Field of the Invention
The present invention relates to a scratch-resistant optical film with a cured coating, and more particularly, to a scratch-resistant reflective film applicable to liquid crystal displays (LCDs).
2. Description of the Prior Art
Since a liquid crystal panel does not emit light itself, a backlight module, as a brightness source, is an important element for the displaying function of LCDs, and is very important for enhancing the brightness of LCDs. Presently, various optical films are used in the backlight module, and the use of such various optical films has become the most economical and convenient solution to enhance the brightness of an LCD panel to optimize the service efficiency of the light source without altering any element design or consuming additional energy. FIG. 1 is a schematic diagram of various optical films contained in a backlight module. As shown in FIG. 1, the optical films contained in a common backlight module include: a reflective film (1) disposed below the light guide plate (2); and other optical films disposed above the light guide plate (2), i.e., from the top to the bottom, a diffusion film (3), brightness enhancement films (4) and (5), and an upper diffusion film (6) in sequence.
An excellent reflective film can improve the brightness, and more importantly, can wholly improve the brightness without reducing the viewing angle. According to actual tests, as the reflectivity is increased by 3-5%, the brightness of the same module will be enhanced by 8-10% under the same conditions.
In recent years, a new technique of using a V-cut light guide plate in backlight modules has been developed. As shown in FIG. 2, the V-cut technique mainly employs one reverse prism sheet (9), and one V-cut light guide plate (8) and one reflective film (7) under the reverse prism sheet, whereas two prism sheets were used in prior backlight modules. Compared with the conventional backlight module, the brightness of the backlight module having a V-cut light guide plate can be enhanced nearly by 30%, and thus the required power can be reduced by one third, which is considerably beneficial to the improvement on power-saving performance.
However, either for the conventional screen printed light guide plate or for the V-cut light guide plate, when it is used together with a reflective film, the optical structure on the reflective film will directly contact the guide plate and thus fine scratches or white spots may occur on the reflective film, which may adversely affect the light uniformity and weaken the mechanical strength of the reflective film.
Moreover, current V-cut light guide plates are normally used together with a silver (Ag) reflective plate. Since an evaporation deposition process is needed, the production rate is slow, the cost is high, and the silver metal is easy to be scratched.
In view of the above, the present invention provides a scratch-resistant optical film to overcome the above-mentioned shortcomings. In the present invention, a novel hard coat solution is used to form a scratch-resistant layer on a surface of a substrate. After curing the hard coat solution, the hardness of the optical film can be improved, so as to avoid scratching the surface structure of the reflective film during operation. The optical film has high transparency and good evenness, and will not warp, thereby achieving the purpose of the present invention.